Adolf sengel



No. 624,986. PateniedMay I6,- |899.

A. SENGEL. CONTINUDUS CURRENT SHUNT MACHINE.

(Application led Nov. 11, 1898.)

@WwW/a UNITED lSTATES PATENT CEEICE.

CONTINUOUSC'URRE SPECIFICATION forming part of Letters NT SHUNT-MACHINE- Patent No. 624,986, dated May 16, 1899.

Application filed November 1l, 1898. Serial No. 696,129. (No model.)

To @ZZ whom, t Duty 'coil/cern.'

Be it known that I, ADOLF SENGEL, professor at the Electrotechnical Institute at Darmstadt, in the Grand Duchy of I-Iesse, Germany, have invented new and useful Improvements in Continuous- Current Shunt- Machines, of which the following is a specification.

As is well known,- the construction of the magnet-winding in continuous-current shuntmachines for high potentials involves great difficulties, because with an increasing potential the cross-section of the shunt-wire employed diminishes with the increasing number of windings, so that on one hand there is an increase in the cost of material and manufacture, while on the other hand there is an increased risk of striking through the magnet-winding in case of careless throwing of the shunt-circuit'current out of circuit. The

two first-mentioned drawbacks are especially noticeable in small machines. Resistances might be employed to diminish the potential at the terminals of the shunt-circuit to any desired extent; but this would entail a pcrmanent loss of energy in the resistance, and g the saving in the manufacture of the magnetwinding would be more or less offset by the increased cost of the resistance.

The constructionhereinafter described permits exciting the magnets in a shunt-machine without any loss and with only half the potential at the brushes.

Figure l illustrates an arrangement of connections of this kind embodying my invention, and Fig. 2 illustrates such an arrangement in combination with a starting resistance.

In the drawings, A indicates the armature of a continuous-current'machine.

C indicates the current-delivery device or commutator, with the two collecting-brushes B and B'. Mounted on the shaft is an insulated collector-ring S, which is conductively connected with any suitable point ofthe armature-winding-for example, by means of the current-collector or commutator-segment sand upon which there rubs a third brush B. lrVhen the machine is set in operation and is normally excited, 'there is produced between the brushes B and B', as is well known, a constant potential-that is to say, a potential which has at every moment the same direction and the same value. Now the potential which exists between the brush B, rubbing on the contact-ring S, and one of the brushes the potential between B" and B it will be seen that the potential between the two brushes is equal to zero when the segment s comesV under the brush B. The potential reaches its maximum when the segment s after half a revolution comes in contact with thebrush B, and itis in this'case equal to the potential at the terminals of the machines B B'. In the other positions the potential B" B has a value which is between the maximum and zero. Consequently the poten tialis a pulsatory one. This pulsatory potential may be conceived to be produced by the combination of a pure continuous-currentand of an alternating-current potential, which are of such amounts that both the continuous-current potential and also the amplitude of the alternating-current potential become equal to half the potential at the terminals. If an inductionless resistance be included between B and B, a current which will also continually vary between zero and a maximum will he produced in this resistance, and this current can also be split up into a purecontinuous current and an alternating current. Both currents are of an amount such as if a continuous-current potential of half the potential of themachine and an alternating-current potential having an amplitude also equal in value to half the potential of the machine were to act simultaneously at the terminals of the resistance. If now the resistance which is inserted be tween B and B has self-induction, the latter will 'not adect the continuous current in any way, but will tend to weaken the alternating current, and ina higher degree the greater the coeflicient of the self-induction and the higher the periodic number or frequency of the alternating current, so that with self-induction and a periodic number of any reasonably high value" the current which is -produced can be practically considered to be a continuous current IOO- having a potential equal to half the potential at the brushes. NOW the shunt-Windings of dynamo-machines have an extremely high self-induction. If, therefore, the ends of the shunt-Winding be placed, as shown in Fig. l, between the brushes B and B, with the inclusion of a regulating resistance R, then even With a 10W periodic number the current strength produced in the shunt-current circuit will reach exactly the same Value as if this circuit Were fed With half the brushpotential B B. In the same manner this arrangement of connections may be employed in shunt-circuit motors. Fig. 2 shows an arrangement of this kind in combination With a starting resistance NV. The other reference-letters are the same as those employed in Fig. l. The connections of the armature are made in the usual manner. One end of the shunt-circuit winding is connected through the contact-bar 7a with one pole of the lead, While the other end is connected to the brush B. tions in motors has further the advantage that so long as the armature is at rest the full Working potential will act at the terminals of theshunt-circuit, and therefore the excitingourrent will be twice as great as in normal Working and the attractive force Will be considerably higher than when the ordinary arrangement of connections is used. IVithincreasing'speed of the armature the potential at the terminals of the shunt-circuit will di- The use of this arrangement of connec-A minish and will reach its normal amount, which is equal to half the potential in the lead When the Whole of the resistance in the armature-current circuit has been cut out.

The rubbing-ring S maybe dispensed with when the armature-Winding is connected at one point with the iron body, and in this manner With the shaft and with the magnet-frame, and the one end'of the shunt-circuit Winding is connected to the frame instead of to the brush B. This does not make any alteration with reference to the mode of operation of the entire arrangement.

Now what I claim, and desire to secure by Letters Patent, is thefollowing:

l. In a shunt-dynamo or shunt-motor the connection of one end of the shunt With a point of the main line and the other end of the shunt with a fixed point of the armature- Winding, substantially as described.

2. In a shunt-dynamo or shunt-motor the connection of one end of the shunt with a delivery-brush of the main line and the other end of the shunt with a rubbing-ring placed in the Winding of the arlnature at a iixed point thereof substantially as described.

In testimony whereof I have signed my name to this specification in the presence of tWo subscribing Witnesses.

ADOLF SENGEL.

"\ Witnesses:

R101-IARD WIRTH, REINHOLD KIND. 

